remove revision id from storage engine if write locker cannot be acquired

arangod/VocBase/LogicalCollection.cpp

@@ -2064,30 +2064,20 @@ int LogicalCollection::insert(Transaction* trx, VPackSlice const slice,
 
   try {
     insertRevision(revisionId, marker->vpack(), 0, true);
+    // and go on with the insertion...
   } catch (basics::Exception const& ex) {
-    res = ex.code();
+    return ex.code();
   } catch (std::bad_alloc const&) {
-    res = TRI_ERROR_OUT_OF_MEMORY;
+    return TRI_ERROR_OUT_OF_MEMORY;
   } catch (...) {
-    res = TRI_ERROR_INTERNAL;
+    return TRI_ERROR_INTERNAL;
-  }
-  if (res != TRI_ERROR_NO_ERROR) {
-    try {
-      removeRevision(revisionId, false);
-    } catch (basics::Exception const& ex) {
-      res = ex.code();
-    } catch (std::bad_alloc const&) {
-      res = TRI_ERROR_OUT_OF_MEMORY;
-    } catch (...) {
-      res = TRI_ERROR_INTERNAL;
-    }
-    return res;
   }
 
   {
-    // use lock
+    // use lock?
     bool const useDeadlockDetector =
         (lock && !trx->isSingleOperationTransaction());
+    try {
       arangodb::CollectionWriteLocker collectionLocker(this, useDeadlockDetector,
                                                       lock);
 
@@ -2102,11 +2092,22 @@ int LogicalCollection::insert(Transaction* trx, VPackSlice const slice,
       } catch (...) {
         res = TRI_ERROR_INTERNAL;
       }
+    } catch (...) {
+      // the collectionLocker may have thrown in its constructor...
+      // if it did, then we need to manually remove the revision id
+      // from the list of revisions 
+      try {
+        removeRevision(revisionId, false);
+      } catch (...) {
+      }
+      throw;
+    }
 
     if (res != TRI_ERROR_NO_ERROR) {
       operation.revert(trx);
     }
   }
+
   if (res == TRI_ERROR_NO_ERROR) {
     readRevision(trx, result, revisionId);